Cell & Molecular Biology Karp Chapters 1-4 Test Exam Questions And Answers

Cell & Molecular Biology Karp Chapters 1-4 Test Exam Questions And Answers If you were to argue that viruses are living organisms, what features of viral structure and function might you use in your argument? - ANSWER- That viruses contain genetic material; that they are capable of producing more of themselves, albeit only inside a host cell; that they contain complex biological macromolecules; that they evolve. These are all important criteria of living organisms. Suppose you were a scientist living in the 1890s and were studying a disease of tobacco crops that stunted the growth of the plants and mottled their leaves. You find that the sap from a diseased plant, when added to a healthy plant, is capable of transmitting the disease, to that plant.You examine the sap in the best light microscopes of the period and see no evidence of bacteria. You force the sap through filters whose pores are so small that they retard the passage of the smallest known bacteria, yet the fluid that passes through the filters is still able to transmit the disease. Like Dimitri Ivanovsky, who conducted these experiments more than a hundred years ago, you would probably conclude that the infectious agent was an unknown type of unusually small bacterium.What kinds of experiments might you perform today to test this hypothesis? - ANSWER- You could examine the filtrate under the electron microscope and determine whether the infectious agent was cellular, i.e., bacterial, or noncellular, i.e., viral. You could try to culture the infective agent. If it was a bacterium, you should be able to culture the agent in the absence of host cells, but not so if it were a virus. You could determine the size of the genome (i.e., the RNA or DNA that constituted its genetic material). If it was cellular, it would be expected to have a much larger genome than if it was viral. Prokaryotic cells can be distinguished from eukaryotic cells by the absence of: a) a nucleus b) DNA c) a plasma membrane d) All of these are absent. - ANSWER- A nucleus Eukaryotic cells can be found in all of the following organisms EXCEPT: a) animals. b) bacteria. c) plants. d) fungi. - ANSWER- bacteria Which of these is NOT a common feature of eukaryotic and prokaryotic cells? a) Mechanisms for transcription and translation b) Genetic information encoded in DNA c) Construction of plasma membrane d) Cytoplasmic organelles such as endoplasmic reticulum and Golgi complex. - ANSWER- Cytoplasmic organelles such as endoplasmic reticulum and Golgi complex All of the following are examples of prokaryotic cells EXCEPT: a) viruses. b) cyanobacteria. c) bacteria. d) mycoplasma. - ANSWER- viruses Model organisms used by cell and molecular biologists include all of the following EXCEPT: a) mice. b) bacteria. c) nematodes. d) orangutans. - ANSWER- orangutans Which of the following structures is the smallest? a) chloroplast b) lipid bilayer c) mitochondrion d) DNA molecule - ANSWER- DNA molecule Which of the following statements about viruses is FALSE? a) They can only be found associated with animal and bacterial cells. b) They are smaller than bacteria. c) They are responsible for numerous human diseases. d) Some of them can become integrated into the DNA of the host's cell. - ANSWERThey can only be found associated with animal and bacterial cells. Contrary to viruses, bacteria: a) contain genetic material in the form of DNA or RNA. b) can be infected by bacteriophages. c) have only 3 or 4 genes. d) are microscopic. - ANSWER- can be infected by bacteriophages. The hypothesis that explains the origin of eukaryotic cells as the result of two or more simpler cells developing a relationship with one another is called: a) panspermia. b) symbiosis. c) evolution theory. d) endosymbiont theory. - ANSWER- endosymbiont theory. A phylogenetic tree based on rRNA sequence comparisons show that the three domains of life are: a) Bacteria, Archaea, and Eucarya b) Bacteria, Plantae, and Eukarya. c) Archaea, Eucarya, and Fungi. d) Archaea, Eukarya, and Cyanobacteria. - ANSWER- Bacteria, Archaea, and Eucarya The evolutionary relationship among cell types can be studied by comparing: a) the sequence of genes. b) the presence or absence of organelles. c) the environment where the cells are usually found. d) the cell shape. - ANSWER- the sequence of genes. Match the following organisms with their category. At least one category will be used more than once.(Eukaryote, virus, prokaryote) Acidophiles... Protists.... Bacteriophage... Nematode... - ANSWER- Acidop